Islamabad officials say authorities have arrested an Indian intelligence officer for his involvement in "subversive activities" in Pakistan and have protested to India's envoy over the case.Two Pakistani security officials said on Friday the man was apprehended in the southwestern Baluchistan province. They spoke on condition of anonymity because they were not authorized to speak to the media on the record.The foreign ministry says it summoned the Indian High Commissioner in Islamabad to lodge a protest over the Indian officer's illegal entry into Pakistan. The ministry says he was involved in violence in Baluchistan province and the city of Karachi.The arrest was announced months after India said militants from Pakistan were linked to a January assault on an air base in India that killed seven Indian soldiers.